function path_set_alias

Set an aliased path for a given Drupal path, preventing duplicates.

Parameters

$path: Path URL. Set to NULL to delete alias.

$alias: Alias URL. Set to NULL to delete alias.

$pid: Path id to update. Set to NULL to create a new alias or to delete a group of aliases.

$language: The language this alias is valid for.

File

modules/path/path.module, line 96

Enables users to rename URLs.

Code

function path_set_alias($path = NULL, $alias = NULL, $pid = NULL, $language = '') {

  /* This function claimed to prevent duplicate aliases but has not done
   * so since the end of 2007.
   * The uniqueness of dst+language pairs was enforced on the database level
   * until D6.16 (march 2010); trying to insert duplicate aliass would yield a
   * database error.
   * From D6.16 onwards, duplicates would silently be inserted, and
   * drupal_lookup_path() consistently uses those newer aliases.
   * While fixing an issue in D6.23, the behavior was reverted to preventing
   * duplicates by the below code. Watchdog errors are now logged instead.
   */
  $path = urldecode($path);
  $alias = urldecode($alias);

  // First we check if we deal with an existing alias and delete or modify it based on pid.
  if ($pid) {

    // An existing alias.
    if (!$path || !$alias) {

      // Delete the alias based on pid.
      db_query('DELETE FROM {url_alias} WHERE pid = %d', $pid);
    }
    else {

      // Update the existing alias.
      // Check if the alias exists already.
      $existing = db_fetch_array(db_query("SELECT pid, src FROM {url_alias} WHERE dst = '%s' AND language = '%s' ORDER BY pid DESC", $alias, $language));
      if (!$existing || $existing['pid'] == $pid && $existing['src'] != $path) {
        db_query("UPDATE {url_alias} SET src = '%s', dst = '%s', language = '%s' WHERE pid = %d", $path, $alias, $language, $pid);
      }
      else {
        if ($existing['src'] != $path) {
          watchdog('path', "The alias for path '@path' (language '@lang') was not updated to '@alias', because the path '@expath' already has the same alias.", array(
            '@path' => $path,
            '@lang' => $language,
            '@alias' => $alias,
            '@expath' => $existing['src'],
          ), WATCHDOG_ERROR);
        }

        // Don't clear cache if we didn't change anything
        return;
      }
    }
  }
  elseif ($path && $alias) {

    // Add this alias to the database, if it's new & doesn't cause conflicts.
    $existing = db_fetch_array(db_query("SELECT src, language, pid FROM {url_alias} WHERE dst = '%s' AND language IN('%s', '') ORDER BY language DESC, pid DESC", $alias, $language));
    if (!$existing || $existing['language'] != $language && $existing['src'] != $path) {

      // A new alias. Add it to the database.
      db_query("INSERT INTO {url_alias} (src, dst, language) VALUES ('%s', '%s', '%s')", $path, $alias, $language);
    }
    elseif ($existing['language'] != $language) {

      // This alias already exists ONLY for 'language neutral': update language.
      // (We can only get here if $language != '')
      db_query("UPDATE {url_alias} SET language = '%s' WHERE pid = %d", $language, $existing['pid']);
    }
    else {
      if ($existing['src'] != $path) {
        watchdog('path', "The alias '@alias' for path '@path' (language '@lang') was not created, because the path '@expath' already has the same alias.", array(
          '@path' => $path,
          '@lang' => $language,
          '@alias' => $alias,
          '@expath' => $existing['src'],
        ), WATCHDOG_ERROR);
      }

      // Don't clear cache if we didn't change anything
      return;
    }
  }
  else {

    // Delete the alias.
    if ($alias) {
      db_query("DELETE FROM {url_alias} WHERE dst = '%s'", $alias);
    }
    else {
      db_query("DELETE FROM {url_alias} WHERE src = '%s'", $path);
    }
  }
  drupal_clear_path_cache();
}